1. Field of the Invention
The present invention relates to a plasma display panel (PDP) of surface discharge type and the method for driving the PDP.
A plasma display panel is used widely for a television set or a computer monitor after the color display thereof has been successfully commercialized. In order to attain further wide use of the PDP, the structure thereof that is suitable for high definition is developing.
2. Description of the Prior Art
As a color display device, an AC type PDP having three-electrode surface discharging structure is commercialized. The surface discharge type has a first and second main electrode as anodes and cathodes arranged in parallel on the front and the back substrates in the display discharge securing intensity. As an electrode matrix structure of the surface discharge type plasma display panel, a xe2x80x9cthree-electrode structurexe2x80x9d is known well in which third electrodes (address electrodes) are arranged so as to cross the main electrodes. One of the main electrode pair is used as a scanning electrode for row selection, so that address discharge is generated between the scanning electrode and the address electrode. Thus, addressing is performed for controlling wall discharge in accordance with contents of display. After the addressing, a sustaining voltage having alternating polarity is applied to the main electrode pair, so that the surface discharge is generated along the surface of the substrate only in the cell having a certain quantity of the wall charge.
A basic three-electrode structure has a pair of main electrodes arranged in each row of the screen. The distance between the main electrode pairs in each row (a surface discharge gap length) is set to a few tens of microns so that the discharge can occur by the application of 150-200 volts.
On the contrary, the distance between the electrodes of the neighboring rows (referred to as an inverse slit) is set to the value that is sufficiently larger than (as large as a few times) the surface discharge gap length so as to prevent undesired surface discharge between rows and to decrease the capacitance. Namely, the distance between the main electrodes of a row is different from that between rows. Another three-electrode structure has N+1 main electrodes (N is the number of rows in the screen) spaced uniformly. The neighboring electrodes constitute an electrode pair for generating the surface discharge. Main electrodes, except those at opposite ends of the arrangement, are related to the neighboring two rows. In the plasma display panel having this structure, interlaced scanning is performed for display.
The surface discharge type plasma display panel having the three-electrode structure includes partitions (i.e., barrier ribs) for defining the discharge space of each row. A stripe pattern of the partition in which partitions having a ribbon shape as a plan view are arranged has an advantage compared with a mesh pattern in which each cell is isolated. In the stripe pattern, the discharge space is continuous over the full length of the screen in each column. Therefore, the discharge probability can be increased by priming, fluorescent layer can be made uniform, and the exhausting process can be, performed easily. As the structure having the discharge space that is continuous in the row direction, a two-layer structure is also known, in which the mesh pattern and the stripe pattern are combined in the height direction.
In the conventional panel structure in which the discharge space is continuous in the column direction, there is a problem as follows. The address discharge in the row selected for addressing spreads excessively in the column direction, and undesired charge is accumulated in the area adjacent to the address electrode in the row neighboring the selected row. When the neighboring row becomes the selected row later, the charge that has been accumulated can lower the address voltage applied to the cell. The lowered address voltage cannot cause an address discharge, and incorrect addressing causes fluctuations of display. Especially in the structure having main electrodes spaced uniformly this can cause addressing errors easily.
An object of the present invention is to suppress the growing of the address discharge in the column direction so that the addressing accuracy can be improved.
In the present invention, the shape or the position of the address electrode is arranged so that the opposed area of the main electrode that is not used for row selection opposed to the address electrode via the decreased discharge space can be decreased. Thus, the address discharge is localized in the opposed portion of the address electrode, i.e., the portion opposed to the main electrode and to be used for row selection.
If the main electrode is made of a transparent conductive film and a metal film, the portion of the metal film opposed to the address electrode causes the address discharge. Therefore, the area of the metal film of the main electrode to be used for row selections opposed to the address electrode, is set sufficiently large so that the reliability of the address discharge can be secured.
According to a first aspect of the present invention, the plasma display panel includes a plurality of first main electrodes for row selection, a plurality of second main electrodes constituting electrode pairs with plural first main electrodes for generating surface discharge on each row, a plurality of address electrodes for column selection, and partitions for defining a discharge space for each column, which is continuous over the full length of the screen. The first main electrodes and the second main electrodes are arranged alternately. Each of the first main electrodes and the second main electrodes includes a transparent conductive film for securing electrode area and a metal film for reducing electric resistance. Each of the address electrodes crosses at least the metal film of the first main electrodes and is patterned in such a way that the area, opposed to the metal film, of the second main electrode is smaller than the area opposed to the metal film, of the first main electrode in the area between the partitions of each column of the screen.
According to a second aspect of the present invention, the first main electrodes and the second main electrodes are spaced uniformly.
According to a third aspect of the present invention, the first main electrodes and the second main electrodes are spaced uniformly and the transparent conductive films of the first main electrodes and the second main electrodes are patterned so as to protrude, at each end of the metal film overlaying thereon, in the column direction and so as to form a T-shape.
According to a fourth aspect of the present invention, each of the address electrodes crosses the metal film of the first main electrodes at the center of the area in the row direction.
According to a fifth aspect of the present invention, each of the address electrodes is patterned in a linear ribbon shape, whose width changes periodically, so that the width at the portion crossing the metal films of the first main electrodes is larger than that at the portion crossing the metal films of the second main electrode.
According to a sixth aspect of the present invention, the first main electrodes and the second main electrodes are spaced uniformly, the transparent conductive films of the first main electrodes and the second main electrodes are patterned so as to protrude, at each end of the metal film overlaying thereon, in the column direction and so as to form a T-shape, each of the address electrodes is patterned in a linear ribbon shape and whose width changes periodically so that the width at the portion crossing the metal films of the first main electrodes is larger than that at the portion crossing the metal films of the second main electrode, and each of the address electrodes is arranged at the center of the area in the row direction.
According to a seventh aspect and a twelfth aspect of the present invention, a method of driving a plasma display panel is provided. The method comprises the steps of displaying odd fields and even fields of an object image; controlling a potential of each of the first main electrodes and the address electrodes independently so as to perform addressing of odd rows, and then applying a voltage for generating surface discharge to the electrode pair of the odd row periodically, while displaying odd fields, and controlling a potential of each of the first main electrodes and the address electrodes one by one so as to perform addressing of even rows, and then applying a voltage for generating surface discharge to the electrode pair of the even rows periodically, while displaying even fields.
According to an eighth aspect of the present invention, a plasma display panel is provided that includes a plurality of first main electrodes for row selection, a plurality of second main electrodes constituting electrode pairs with the plural first main electrodes for generating surface discharge on each row, a plurality of address electrodes for column selection, and partitions for defining a discharge space for each column, which is continuous over the full length of the screen. The first main electrodes and the second main electrodes are arranged alternately. Each of the plural address electrodes is patterned so as to cross the first main electrodes and not to cross the second main electrodes in the area between the partitions of each row in the screen.
According to a ninth aspect of the present invention, the portions of the address electrodes crossing the second main electrodes are insulated by the partition from the discharge space.
According to a tenth aspect of the present invention, the first main electrodes and the second main electrodes are spaced uniformly.
According to an eleventh aspect of the present invention, the first main electrodes and the second main electrodes are spaced uniformly and the transparent conductive films of the first main electrodes and the second main electrodes are patterned so as to protrude at each end of the metal film overlaying thereon in the column direction and so as to form a T-shape.